Copying sound events taken in amplitude records



Feb. 22; 1944. G F 2,342,464

COPYING SOUND EVENTS TAKEN IN AMPLITUDE RECORDS Filed March 12, 1941 3Sheets-Sheet l Feb. 22, 1944. FRIE 2,342,464

COPYING SOUND EVENTS TAKEN IN AMPLITUDE RECORDS Filed March 12, 1941 5Sheets-Sheet 2 iyl.

G. FRIES Feb. 22, 1944.

COPYING SOUND EVENTS TAKEN IN AMPLITUDE RECORDS Filed March 12 1941 3Sheets-Sheet 3 Patented Feb. 1944 COPYING SOUND EVENTS TAKENIN AMPLITUDERECORDS Gustav Fries, Berlin-Chariottenburg, Germany;

vested in the Alien Property Custodian Application- March 12, 1941,Serial at. 383,059 Germany February 10, 1940 The present inventionrelates to a method of copying sound records oi the amplitude type. Moreparticularly the invention relates to a method of copying verylongcoherent sound records which with the aid oi a needle or a luminoussound have been recorded upon a sound carrier as transverse vibrations,i. e., in amplitude or indented records. As a rule, a film strip is usedas sound carrier.

It is well known to engrave on a strip-like sound carrier acousticevents in the form of grooves by means of a cutting needle and toclosely fill the strips with such grooves. By means of such sound stripsacoustic events of nearly any desired duration may be recorded andreproduced. With a length 01 strip of, for instance, 100 m. having 100grooves upon each side, the durationof play is about 12 hours, providedthe cutting or scanning speed amounts to 45.6 cm.zper second. The natureof the strip as well'as the density and the arrangement of the-grooveson both sides render the copying ofthe' strip rather difficult. Somecopying methods 'cannot'be used at all particularly the veryadvantageous optical methods. These and other reasons have heretoforemade the copying of such strips practically impossible, particularlystrips of this length, as often as is desired.

Moreover, it is also well known to produce by means of luminous signalsupon one side of a strip-like sound carrier several sound traces side bysidein transverse signals. Such sound traces. recorded with luminoussound, have already been treated in a manner similar to that of a lightcopying method by changing theseltraces into a gelatin swelling relief.producingthereirom intermediate galvanos and then using these forcopying the original sound carrier. In another connection finally it isknown to change by means of etching a luminous sound record into aneedle sound record by recording the luminous sound in transversesignals in a trace the brightness of which changed from the middle lineto the margins so that on etching of the trace recorded with" luminoussound anelevated or deepened reproduction of th diflerently lightedportion=was obtained which either directly resulted in a needle soundtrace or during copying couldbe changed into such a sound trace. i

"The present inventiorahowever, solves with the' use of simple means theproblem of directly producing from'an original record a matrix that can:b'eused without. the originaLiorthe purpose of '-copying, that is:prepared mechanically. by

electrolysis or in any other manner and par.

ticularly without subjectingf the original sound strip tothe actionof'achemical bath. By this method a practically unlimited number of copies01' greatest exactness can be made without v any danger of wear. Ifdesired, the new method may be carried out fully or semi-automatically.A better understanding of this invention can be had from the followingdetailed description when considered with the drawings-in which:

Figures 1 and 2 diagrammatically show ifunda-,

mental details;

Figure 3 diagrammatically shows a portion oi the device within-which thecopper'strlp serving as matrix is cleaned;

Figure 4 diagrammatically shows the device for drying the strip andapplying the copying layer,

and, moreover, illustrates the copying and de- 'ment for impressing bothsides of a strip the two ends of which are later on stuck together toform an endless reel;

Figure 10 diagrammatically shows the point of connection of the coppermatrices shown in Figure 9; and

Figure 11 diagrammatically shows the register of the point of stickingtogether the endsoi' the strip.

The new copying method begins with sound events recorded in transversesignals the width of the trace of which shows differences in brightness.These differences of brightness may be due to a difierently strongexposure or the luminous sound trace or to a difierent thickness of thestrip over the width oi the needle sound trace. The new copying methodconsists in producing from the record, for instance, photochemically aprint form, or an intaglio form, refraining from effecting prints fromthese forms 'but preparing by impressinga copy or a plurality of copiescapable of being scanned by a needle. For the purpose of the inventionthe knowledge is of im portance that in all printing methods, operatingwithout a screen, diiierences in brightness must or gap form upon alight sensitive film strip and;

being controlled by the sound frequencyln such a manner that a wave linein the manner of the Berliner record (amplitude or transverse record) isproduced as in connection'with a disc layer in dependence on theblackening of the negative and eflect a reduction of the water so]-ubility of said layer. The exposed pigment paper band III is transferredto the copper strip V and then rinsed with water. The portion of thegelatin layer which remains soluble is washed away, whereas the exposedportion is retained as groove relief,-because it hardened by theexposure. The etching of the copper record, however, with differentbrightness in the width of the trace. After an ordinary development, therecord appears as a wave line the width of which variesin darkness,whereas the partof the film strip not subjected to the light remainstransparent. To obtain a definite profile of the material betweenadjacent grooves upon the matrix it is of particular importance that thelightgap changes from the middle towards both sides in the manner of agray wedge.

This gray wedge-like change of brightness may be decreasing orincreasing from the middle of the strip outwards. The middle of thestrip, therefore may be the darkest or the brightest portion. The latterparticularly simple case is shown in Fig. 1.

The invention, moreover, consists in the knowledge that it is of noimportance for the transferoi the intaglio method, known in the printingart upon the copy of sound films, whether the original record had beenmade with the aid of luminous signals or by means of a needle sound. Thetransverse luminous record and the needle record are equivalent for thenew method and, therefore, may be replaced one for the other wheneverdesired, The examination of a needle sound record by means of light raysalso results in a record strip the brightness of which changes from themiddle line towards the margins. kinds of record, therefore,photo-chemically allow the production of a metallic printing form havingsound records in relief, i. e.,the production of metallic forms whichmay be used for In the sense of the invention both.

the direct production-of a large number of very exactly impressedcopies.-

After these explanations a short hint only is required for the averageexpert to understand that the reproduced needle sound copies may bechanged to a strip-like transverse record extending upon the surface ofthe carrier and capable of being scanned by luminous sound by means of asimple further step in the method, 1.. e., by means of a light copyingprocess. Finally, it is clearly to be seen that in copying in accordancewith the new method, the original sound strip is subjected to light raysonly and. is in no manner chemically or otherwise changed.

In the drawings the, means for carrying out two of the various possiblemethods are shown according to which the originally produced film may berecorded as a light strip the width of which is of different brightness.

Fig. 1 diagrammatically shows the production of a matrix. II is thenegative of I. By means of this negative the pigment paper III isexposed. The light rays, indicated by arrows, enter the uncoveredportions of the negative, more or less penetrate the chromium gelatinfinished matrix consists of five operations.

strip with a solution of iron chloride dissolves the copper first atsuch points at which the copper strip is mostweakly covered by thegelatin relief,

Lwhereasftheietching solution slowly penetrates theswelling gelatin andthe etching occurs later on. In this manner the groove relief with allits finen'esses is transferred upon the copper strip. After; etching,rinsing of the copper strip is effected and the'copper strip matrix isfinished.

'As may be seen from Fig. 1 the method beginning with taking the recordand ending with the One of these operations maybe omitted, if theoriginal exposure I is made upon a photographic reversal film, becausethen the production of the negative II is rendered superfluous.

The exposure may also be effected without the us of a gray wedge. Inthis case" the etching would be eifected in accordance'with the lineetching method by which the materiaI between the grooves is profiled bymeans of repeated colorings and etchings with differently strong etchingsolutions.

For the manufacture of sound films on a factory scale a particularadvantage of this step of the method according to the instant inventionconsists in this that in spite of the fact, that the copy is to bescanned by a needle guided in the sound groove, the needle is dispensedwith on taking the record because the needle is rendered blunt bytakingrecords extending over several hours, and that, moreover, due tothe needle being dispensed with no chippings are produced. Consequentlyalso the unavoidable inexactnesses and uncleannesses are dispensed withwhich ac- .company any finishing based upon removal of chippingsoperations.

Should it be desired forspecial purposes to listen to a record at once,this may be effected by means of a cutting needle. Hereby one side ofthe sound carrier which also may be a disc record is provided with athin black layer (shown in Fig. 2 at I). Or for reproducing purposes therecord is copied upon a photographic film so that for the exposure ofthe matrix the sound groove is bright. To effect the exposure the record'I is brought upon the copper strip III provided with the copying layer11. After the exposure the development, rinsing and etching is efiected.Hereby it is to be considered a favorable circumstance that by theprofile of the cut groove the light permeability of the sound carrier,now transparent at this point, is as good as if the graywedge increasingin darkness from the middle towards both sides would have acted in thesame manner as during taking the record with light gap. If the record inform of grooves has been made upon a strip which has no black coveringor coating the latter may be applied after taking, the record, as thecolor, for instance by rollin COV- ers the surface of the strip'only,whereas the grooves, due to their depth, being left free. T1

In each case an intermediate negativelof the record is used as copywhich negativehaslbefen in contradistinction .to deforming Each methodmay be used which results in printing forms in relief which arepractically free of screens and mechanically of sufficient strength andthe margins of which are particularly exact.

Figs. 3-7 show by way of example a construction adapted forcarrying out,with photochemical means, the entire novel, copying method. As thenumber of copies is very large there may also be the question of areproduction method. The entire device is represented in subdividedportions in Figs. 3, 4, and 6. This device in: a coherent operationallows the production of. copies of sound records upon film strips whichare scanned from the copyby means of a needle.

In carrying out the method according to the invention the fact isutilized that for instance chromium gelatin has the property of. losing,depending on the magnitude of the entering amount of light, more or lessits solubility in water under the action of this light. Chromiumgelatin, therefore, is suitable as carrier for the sound copy of a soundrecorded upon a film by means 'of light.

A mixture of fish-glue, distilled water, ammo nium bichromate andammonia for instance is suitable as copying layer.

The action is such that light rays falling into the layer more or lessactively act upon the copying layer in accordance with the density ofthe film to be copied andin this -manner effect a change of the watersolubility of the layer. The change of the water solubility-is thestronger, the deeper the light penetrates. At the most transparentpoints 'of the film to be copied, therefore, the change of the watersolubility is largest and at the most covered points it is mostweakened.

Wound uponthe drum l is the metal strip, for instance a copper strip,serving as matrix which, as shown i F g. 3, enters the tank 2 whenimwound from said drum I. In this tank the copper strip is cleaned bymeans of a swabber anda pulp of prepared chalk and a caustic alkalisolution. In'the tank 3 rinsing with water is ef-' fected which issupplied by a pipe 4 and discharged by a pipe 5. The tanks 6 and! alsoserve for cleaning purposes. The tank 6 preferably is filled with spiritsuch as alcohol and the tank I with a mixture of water and spirit. .Thedrive for the feed of the copper strip 3 is effected by a motor 9 whichalso drives the swabber lb. The rollers II and I 2 effect drying of thestrip. A cross-section of the strip 8 taken along the line AA in Figure3 is shown at A in Figure 6.

The tank l3 contains the mass of the copying layer which, for instance,may be of the already mentioned composition and is applied at It uponthe copper strip 8 in a thickness of about 0.2 mm. On the way to thecopying lamp IS the copying layer is dried and for this purpose acombined heating apparatus and centrifugal fan i5 is pro= videds Across-section of the strip 3 with the copying layer applied thereto,taken along the line 3-3 in Figure .4, is shown at B in Figure 6.

As the strip 8 moves below the lamp It, the iilm 25 to be copied isunwound from the drum 23 and guided between endless strips ii and It bythe rollers I9, 23. 2i and 22 and pressure is applied to the strip 3provided with the copying layer 26. The transparent guide strip l8hereby has the purpose of ensuring a good contact be tween the strip 23provided in the example shown with four sound traces 34 and the strip 8.The

'produced as printing form for instance photochemically by means knownin the printing art.

various strips and copying layer,are shown in cross-section at C inFigure 6. This cross-sectional view was taken along the line 0-0 inFigure 4. After exposure by the lamp IS, the strip 25 is wound upon thedrum 24, while the strip 8 carrying the copying layer 23 is developed inthe tank 21 with water, supplied and discharged by pipes 23 and 23respectively, by the fact that the portion of the copying layer 23 whichremains water soluble due to the light rays notpenetrating is rinsedaway, whereas the water unsoluble portion remains as webs between thegrooves. A cross-sectional view of the strip 8 after emerging from thebath in tank 21, taken along the line D-D of Figure 5, is shown at D inFigure 6. Before the strip enters the etching bath in the tank 3|, thelower side of same is covered at 32 with a fast drying acid proof layerof lacquer which prevents. the etching liquid from attacking the lowerside of the copper strip 8.

The etching operation is such that the etching liquid, in the methoddescribed, by way of example, a solution of iron chloride, first attacksand dissolves the copper strip covered with the groove relief formed bythe copying mass remaining after development, at such points at whichpreviously the light has most strongly impinged, and that the chloridedissolves the copper the deeper, the longer it acts. Practically,therefore, the groove relief, from the copying mass is transferred tothe copper strip, as the chloride is prevented from attacking the copperstrip by the groove relief acting as protective layer.

In the tank 33 a last rinsing of the strip 8 with water is effected andthen the copper strip matrix is finished. The sound grooves now-remainupon the copper strip 8 as webs 34 in relief. A cross-section of thestrip after emerging from the bath in tank 33, taken along the line E-E,is shown at E in Figure 6. 1 vOn further movement of the finished matrix8 the latter reaches the device shown in Fig. '7.

Here the film strip 36, consisting of plexy glass, Cellophane or asimilar material suitable as carrier for sound grooves to be providedwith matrices and unwound from the drum 35 and eventually a secondmatrix So for impressing the other side of the sound groove carrier 36are supplied.

The two matrices 8 and 8a are moved towards each other. and with thecarrier 33 between same are, exactly guided by the guide members 31 and31a, introduced between the rollers 33 and 39, between which theimpression of the groove webs 34 in the groove carrier 38 is effected.To facilitate the impressing operation, the rollers 38 and 39 are heatedand maintained hot. Across-section of the strips 8, 3a, and 33, takenalong the line F-F in Figure '7, is shown at F-F in Figure 8. After thestrips 3, 8a, and 36 have passed through the heated rollers 38 and 33,they appear as shown in the cross-sectional view G-G of Figure 8, whichwas taken along the line G-G of Figure 7. After effecting theimpression,the now finished sound strip is wound upon the drum 43 and the matrices8 and 8a are further moved to eventually efiect further impressing.

The matrix may directly after or during the manufacture be listened toand this electromagnetically if the matrix is provided'with reliefs, by

scanning if the matrix has grooves by means of which profiles in reliefare impressed which in turn are capable of being electromagneticallvscanned. All the profiles may be scanned during the production andopposed upon frequency meters in such a manner that difierences in theexactness of reproduction are noticeable at once optically oracoustically by rneans of a measuring indication The final positive,therefore, may obtain a deepened impression or an impression in relief.The impression in relief is by means oi modern printing methods for thematrix easily be worked with such sharp or exactly formed edges frondthe surface oi the sound carrier that the groove between the uppersurface and the fiani: of the impression may be scanned by a needle,provided an indented record has been impressed. An intensity record inrelief and .also the above mentioned indented record in relief may,furthermore, be rendered conductive with the use of known means and maythen electromagneti cally be scanned.

in Figure 9 there is illustrated diagrammatically an arrangement forimpressing both sides of a strip, the two ends of which are to he joinedtogether to form an endless reel. Fragments of the strips H and J areshown in perspective in Figure 10. Mter the strip K has received im-'pressions on both sides thereof, it is joined together as shown inperspective in figure 11 to form the endless reel.

What I claim is:

l. The method of reproducing a sound record having a sound track thereoncomprising clean ing the transverse suriace'oi a moving metallic strip,depositing a layer of a light sensitive material on the cleaned surfaceof said moving strip as it moves from the cleaning treatment, thesolubility of' said light sensitive material being decreased on theexposure of said material to light, causing said strip after applicationof the light sensitive material thereon to pass in con.- tact with anegative of the sound record to be reproduced while directing rays oflight through said negative and onto the surface of said moving striphaving said light sensitive material thereon, Washingthe moving stripand dissolving the soluble portions of the light sensitive materialafter the moving strip passes said negative lll aerated whereby to forma Web and groove relief on the treated surface of the moving strip,etching the treated and washed surface oi the moving strip followingsaid washing step to transfer the web and groove relief to said surface,and then simpressing the web and groove relief of said mov ing striponto a film strip by causing said moving strip to pass adjacent to saidfilm strip while pressing said moving strip into the mm strip, saidmetal strip, negative, and film strip moving concurrently at a uniformspeed.

2. The method as claimed in claim 1 wherein the etching step is carriedout by the chemical action of an etching solution which will attack themetal of the, moving strip.

3. The combination in a device for reproducing a sound record having asound track of a movably supported metallic strip, drive means formoving said strip from end to end of said device, cleaning rneansthrough which said metallie strip passes arranged near one end of saiddevice, means containing light sensitive material positioned forwardlyof said cleaning means fordepositing a. layer of said material on asurface of said metallic strip, a light source arranged forwardly ofsaid depositing means and adapted to direct light rays onto the surfaceof said metallic strip having the light sensitive material thereon, anegative of the sound record to be reproduced being interposed betweensaid light source and said metallic strip, means for supporting saidnegative anumovlng it while in contact with the metallic strip,developing means through which said metallic strip passes located

